/,'irinr qf Recent Geological Literature, -V-h 
streams and tidal estuaries, which extend up to the eastern edge of 
the Piedmont plateau. The land of the Coastal plain rises gradually 
from the coast towards tlie interior and reaches in places an altitude of 
300 feet or more. The Piedmont plateau includes about one-fourth of 
the state. Here the country is broken by low, undulating hills, rising 
higher towards the west. The streams are rapid and are actively cut 
ting down their channels. The Appalachian region forms the western 
part of the state. Here are a series of parallel mountain ranges, with 
deep valleys between them, and the whole is cut at almost right angles 
by the Potomac river. Many of the ranges reach a hight of 2,000 feet 
above sea level and some of over 3,000. A number of pages are devoted 
to the climate of the state, and there are several charts showing the 
temperature, precipitation, etc., for different parts of the year. 
The state of Maryland, although of small size, is so situated that it 
presents an almost complete sequence from the most ancient to the 
recent formations. The three different topographical provinces are also 
geological provinces, so that in a general way it can be said that tin- 
Piedmont plateau is occupied by the ancient crystalline and semi-crys- 
talline rocks, the Appalachian legion by the Paleozoic and the Coastal 
plain by the Mesozoic and Cenozoic deposits. 
The Piedmont plateau is regarded as having a fan structure, the 
axis of the fan starting from the (ireat Falls of the Potomac and running 
in a general northeasterly direction; this axis is not coincident with 
nor parallel to the line between the more crystalline rocks to 
the east and the less crystalline to the west, but lies in the latter. 
The country rocks of the eastern part of this plateau are mostly 
gneisses which now show no evidence of a clastic origin, but their sed- 
imentary character may be inferred from the rapid alternations of beds 
of different composition and from the nature of the rocks intercalated 
with them,- marbles, and ijuartz schist. Three types of igneous rocks 
have broken through and more or less modified the gneisses; these 
eruptives are, in the order of their ages, gabbro. peridotite and pyrox- 
enite, and granite. In many places these have been subjected to in- 
tense dynamic action and have undergone profound alteration. The 
western part of the plateau is composed of little crystalline or semi- 
crystalline rocks: towards the east these become more crystalline and 
stand nearly vertical. The geological position of these rocks has not 
been positively proven by fossils, hut ii is very probable that they are 
Cambrian sandstones, Trenton limestones and Hudson river shales in 
a more or less metamorphosed condition. It is here thai more d< 
tailed stratigraphical work is needed. The Newark iTriassic) sand 
stone occurs along the western edge of these rocks and overlaps them 
to some extent. 
The Appalachian province shows an almost complete sequence of the 
sediments of the Paleozoic. On the east the Blue ridge and the Great 
valley exhibit faulted Cambrian, Trenton and Hudson River rocks, be- 
neath which in places are older eruptives,— rhyolite, basalt and granite. 
The province west of this exhibits in the most characteristic manner 
